1. Field of the Invention
The present invention generally relates to dual flush mechanisms for toilets, and, more particularly, a dual flush mechanism which utilizes only a single flush valve.
2. Description of the Prior Art
Various dual flush toilet mechanisms have been developed over the years for the purpose of providing the user with a choice of a "short" or partial flush to carry away liquid waste and a "long" or full flush for solid waste. The benefit of a dual flush arrangement is the potential savings of large quantities of water in times where water is becoming an increasingly scarce and valuable commodity.
Previous dual flush mechanism designs have characteristically used two separate flush valves, the full flush valve being located at a low level within the tank to receive a full volume of water, and the partial flush valve being located at mid-level within the tank to receive only a portion of the tank volume. In order to replace conventional flushing mechanisms with such dual flush mechanisms, it was necessary to replace both the pre-existing conventional single flush valve, and its associated plumbing, with a two flush valve configuration, a prospect which was too complicated or costly for the ordinary user.
The inventor, in response, developed a dual flush mechanism which operates with only a single flush valve, and which is simple to install and maintain, for which U.S. Pat. No. 4,764,995 was issued. The construction of this dual flush mechanism, however, was somewhat complex, particularly in the use of rack and pinion gearing to control the partial flush capability. A need exists to further simplify the dual flush mechanism of that patent, thereby decreasing its cost and increasing its reliability and availability.